Non-Patent Document 1 reports that, when magnetization of a ferromagnetic thin film is time-modulated, radiation of a coherent terahertz electromagnetic wave is observed. However, the technique described in Document 1 merely discloses magnetized modulation not by emitting an acoustic wave, but by emitting femtosecond laser light.
In addition, measurement by an acoustic wave (typically, supersonic wave) is also popularly used as a non-destructive inspection of various structures. This is because the acoustic wave has an advantage of having a high internal transmittance for an object such as a metal or a concrete block through which transmission of light is usually difficult. However, the use of such an acoustic wave has been limited to inspections or diagnoses of a mass density distribution and elastic property of a measurement object.
Under the aforementioned circumstances, the inventor of the present invention proposes a property measuring device for measuring a measurement object by an acoustically stimulated electromagnetic field which is applicable to various types of objects as measurement objects, and a method thereof (Patent Document 1).